You are here: the mysterious architecture of the universe – in pictures

You are here: the mysterious architecture of the universe – in pictures

Astrophysicist J Richard Gott leads us on a mind-expanding tour from the familiar precincts of the solar system to the Great Wall of galaxies, the cosmic web and beyond

Captions by J Richard Gott

Wed 27 Apr 2016 07.38 EDT
Last modified on Thu 22 Feb 2018 07.38 EST

The Earth seen from the moon

Astronomers measure distances by the time it takes light to travel across them. The light captured in this image of the Earth took about 1.3 seconds to travel to the Apollo astronauts holding the camera, so astronomers say the moon is 1.3 light seconds away. We must move outward to larger realms to find the cosmic web of galaxies

The solar system

Here we see the almost-circular orbits of the outer planets – Jupiter, Saturn, Uranus and Neptune – edge on. Neptune’s orbit measures eight light hours across. The Earth’s orbit is only 1/5th the size of Jupiter’s, measuring only 16 light minutes in diameter, too small to be seen in this picture. Instead we can see the elliptical orbits of Halley’s comet and the icy Kuiper-belt objects Pluto, Eris, and Sedna. The distance from the sun to the nearest star is much, much bigger. Instead of minutes or hours, it takes four years for light to reach Alpha Centauri

Simulated view of the Milky Way galaxy as seen from above

The Milky Way galaxy, where we live, is even bigger still. It measures 100,000 light years across and contains 300bn stars. Within the range of the Hubble space telescope are 130bn other galaxies. But how are these galaxies arranged in space? What is the architecture of the universe?

The Bullet Cluster

Galaxies appear in clusters. The Bullet Cluster, which is 3.7bn light years away, formed when two clusters of galaxies collided and passed straight through each other. The debris from the collision can be seen glowing with x-rays and is shown here in red between the clusters, while the dark matter thought to hold each cluster together is indicated in blue

The honeycomb model

During the cold war, the Soviet school of cosmology favoured a high-density connected honeycomb of galaxies punctuated by isolated empty voids.The American school, by contrast, held that galaxies are arranged in isolated clusters spread through a low-density sea, like meatballs floating in a thin soup

My high-school science project

Cosmic inflation suggests large-scale structure comes from random quantum fluctuations in the early universe. I realised this means high- and low-density fluctuations must have an equivalent geometry. This is a feature of sponge-like geometry, as I knew because of a high-school science project on sponge-like polyhedra that I took to Japan. Adrian Melott, Mark Dickinson and I showed how gravity grows initial fluctuations into a cosmic sponge, with filaments of galaxies connecting great clusters of galaxies and tunnels connecting low-density voids: the cosmic web

The cosmic sponge

Studies of large scale-structure by our topology group progressed to larger and larger regions over the years. All showed high-density regions with a spongelike topology as depicted by this pair of observational samples from the Sloan Digital Sky Survey (2006) containing over 400,000 galaxies

Prominent filaments in the cosmic web

Each dot in this image shows a galaxy, with the Earth at the very bottom. The CfA2 Great Wall stretches across the lower section, a structure about 300bn light years away from Earth that is 758m light years long, making it the largest known structure in the universe when it was discovered in the late 1980s by Margaret J Geller and John Huchra. At the top is the Sloan Great Wall, a formation about 1bn light years away that measures 1.37bn light years across, which I found with Mario Jurić in 2003

Millennium Run computer simulation showing the cosmic web

This computer simulation of galaxy clustering run by a European consortium in 2005 shows a web of filaments connecting clusters. This reproduces closely the types of galaxy filaments connecting clusters which we see through telescopes – as shown in the previous image

Our view of the cosmic web

This all-sky infrared survey shows our Milky Way galaxy in the foreground, seen edge on from our position within the disk, with distant galaxies seen as dots in the background. The giant filaments seen here are the traces of tiny quantum fluctuations that took place in the tiniest blink of an eye right at the dawn of the universe 13.8bn years ago. These submicroscopic variations are now written in letters of almost unthinkable size all the way across the sky, and we have managed to read them